TUMBLING BEHAVIOR OF NEMATIC WORM-LIKE MICELLES UNDER SHEAR-FLOW

The report on the tumbling instability occurring in nematic solutions of worm-like micelles made of surfactant and subjected to low shearing fields (gamma similar to 1 s(-1)). Results obtained by theology and s mall-angle neutron scattering under shear are in good agreement with t he mesoscopic domain theory developed recently for textured materials (such as liquid-crystalline polymers). When a stationary shearing is a pplied to these solutions, the tumbling results in oscillations in the shear stress responses, which in addition exhibit the scaling laws us ually observed in liquid-crystalline materials. The neutron patterns o n the other hand reveal that the average texture orientation increases after cessation of a shearing in the tumbling regime.